CN1331270C

CN1331270C - Wave guide filter

Info

Publication number: CN1331270C
Application number: CNB200410030091XA
Authority: CN
Inventors: 多米尼克·洛海因东; 沙利纳·古根; 弗朗索瓦·巴龙
Original assignee: Thomson Licensing SAS
Current assignee: Thomson Licensing SAS
Priority date: 2003-02-03
Filing date: 2004-02-03
Publication date: 2007-08-08
Anticipated expiration: 2024-02-03
Also published as: US20040183627A1; KR20040071061A; JP2004242303A; FR2850792A1; CN1534824A; EP1443588A1

Abstract

The present invention provides a particularly small waveguide type filter that can be easily adapted to microstrip circuits. The waveguide filter comprises at least three resonant cavities (14) to (19) coupled to each other. The filter is coupled to a microstrip circuit placed on a substrate (10). At least one cavity (14, 15, 18 and 19) is located on one side of the substrate (10) and at least one other cavity (16, 17) is located on the other side of the substrate (10). The cavities distributed on each side of the substrate (10) have the effect of greatly reducing the size of the filter. The invention also relates to an outdoor transmitting unit comprising said filter.

Description

Waveguide filter

Technical field

The present invention relates to small-sized waveguide filter, especially, such filter will be used to microwave transmission system.

Background technology

Under the situation of the satellite broadcasting in the Ka wave band, emission system must be observed ETSI EN301459 suggestion.The example of outdoor transmitter unit has been shown in the accompanying drawing 1.

Outdoor emission system receives the next signal of indoor unit from afar at midband.First amplifier, 1 amplifying signal also sends it to frequency mixer 2.It is emission band with institute's amplifying signal transposition that oscillator 3 cooperates frequency mixer 2.4 amplifications of second amplifier are sent to band pass filter 5 from the signal of frequency mixer 2 and with institute's amplifying signal.Band pass filter 5 is selected emission bands and with high other frequency of elimination that decays.The 3rd amplifier 6 amplifies through the signal of filtering and sends it to antenna.The antenna (not shown) for example is a kind of trumpet type radiating guide, and it is placed in the face of paraboloidal reflector.

The technology that outdoor unit adopts can for example be worked under 30GHz greatly in very high frequency.Especially, well-known technology is a micro-band technique.Yet, under micro-band technique, produce band pass filter 5 and just brought some problems, promptly the quality factor q of the filter under this technology is not very high.A kind of waveguide filter with very high quality factor q can be used, but this makes aspect circuit size very big usually.

Summary of the invention

The invention provides a kind of small-sized waveguide filter, and it can easily be suitable for microstrip circuit.According to the present invention, all be distributed with cavity in each side of substrate, so just have the effect that can significantly reduce its size.

The present invention is a waveguide filter, comprises at least three resonant cavitys that intercouple, and filter is coupled on the microstrip circuit that is positioned on the substrate.At least one cavity is positioned at a side of substrate, and another cavity is positioned at the opposite side of substrate at least.

Preferably, the side that is positioned at respect to substrate of cavity is by electricity is closed by the ground plane of substrate supports.The coupling that is positioned at least two cavitys of the arbitrary side of substrate is to carry out by ground plane or by the ground plane of separating described cavity.Substrate is divided into groove, and the edge of groove is metallized.Coupling between one of them cavity inlet of microstrip circuit and filter is that the groove by the ground plane of described cavity carries out, and described groove is positioned under the microstrip line of open circuit.

According to a special embodiment, filter comprises: first cavity that is positioned at first of substrate, the ground plane that substrate is run through first coupling slot covers, and first microstripline is located on second of substrate on the coupling slot, so that be coupled described filter to microstrip circuit; Second cavity that is positioned at first of substrate is coupled to first cavity by first transverse groove; The 3rd cavity that is positioned at second of substrate is coupled to second cavity by second coupling slot that runs through substrate; The 4th cavity that is positioned at second of substrate is coupled to the 3rd cavity by second transverse groove; The 5th cavity that is positioned at first of substrate is coupled to the 4th cavity by the 3rd coupling slot that runs through substrate; The 6th cavity that is positioned at first is coupled to the 5th cavity by the 3rd transverse groove, substrate is covered by a ground plane that is run through by the 4th coupling slot, second microstripline is located on second of substrate on the 4th coupling slot, with described filter coupled to microwave transmission circuit.

The present invention also is to be the outdoor transmitter unit of emission band with signal from the midband transposition, described unit comprise use micro-band technique with circuit production on substrate, described circuit comprises amplifying device as defined above, conversion equipment and filter.

Description of drawings

After having read the following description, the present invention will more clearly be understood, and its feature and advantage will become obviously, and given explanation is with reference to following accompanying drawing:

Fig. 1 shows the outdoor transmitter unit of prior art;

Fig. 2 shows the decomposition diagram of filter of the present invention;

Fig. 3 shows the top view of filter as shown in Figure 2;

Fig. 4 shows the cross section view of the parts circuit of identical filter as shown in Figure 3.

Embodiment

Owing to illustrated, will no longer be described in detail to accompanying drawing 1.Yet, in remaining explanation, will be referred to the part of accompanying drawing, the present invention has replaced band pass filter 5.

Accompanying drawing 2 to 4 shows the filter 5 of made of the present invention under micro-band technique.Accompanying drawing 2 to 4 corresponds to the cross sectional view along the A-A line shown in decomposition diagram, top view and Fig. 3 respectively.In these three accompanying drawings, identical reference marker is corresponding to identical part.The accompanying drawing 2 to 4 of part is formed in following explanation with reference to the filter that illustrates from different perspectives.

Substrate 10 is supporting the microstrip circuit (not shown) of the remainder of the circuit that corresponds to the outdoor unit shown in the accompanying drawing 1.The upper surface of substrate 10 has first microstrip line 11 of the output that for example is electrically connected to amplifier 4.The lower surface of substrate almost is grounded 12 on plane and covers fully.Second microstrip line 13 is placed on the upper surface of substrate, and second microstrip line has the input that for example is electrically connected to amplifier 6.First and

second microstrip lines

11 and 13 have constituted the input and the output of filter of the present invention respectively.

Described in described example, filter 5 is by 14 to 19 waveguides of being formed of first to the 6th resonant cavity.First, second, the 5th and the 6th

resonant cavity

14,15,18 and 19 is machined in the metal base 20.Pedestal 20 is electrically connected on the ground plane 12.Ground plane 12 further is used for the described

cavity

14,15,18 and 19 on the electric closed base 20.Thereby metal base 20 can extend to the whole surface of substrate 10 and make that described substrate 10 is not flexible and guarantee that ground plane 12 has better conductibility.Third and fourth cavity is machined in the metal cap 21.Metal cap 21 is set on the substrate 10, is positioned at above the ground plane 22 on the whole surface that extends to cover 21.Ground plane 22 further is used for the

cavity

16 and 17 of electric closed cap 21.For example, cover 21 is fixed on the pedestal 20 by the screw (not shown), therefore further provide cover 21, the good conductivity between pedestal 20 and

ground plane

12 and 22.

First microstrip line 11 is by being coupled to first cavity 14 by being manufactured on the printing of first on the ground plane 12 groove 30.Second cavity 15 is by being coupled to first cavity 14 by first transverse groove 31 of machinery production on pedestal 20.The 3rd cavity 16 is coupled to second cavity 15 by first metallic channel 32.The 4th cavity 17 is by being coupled to the 3rd cavity 16 by second transverse groove 33 of machinery production on cover 21.The 5th cavity 18 is coupled to the 4th cavity 17 by the second metallized groove 34.The 6th cavity 19 is by being coupled to the 5th cavity 18 by the 3rd transverse groove 35 of machinery production on pedestal 20.Second microstrip line 13 is coupled to the 6th cavity 19 by being manufactured on the printing of second on the ground plane 12 groove 36.

The first and

second printing grooves

30 and 36 are made on the metal level of forming ground plane 12.First and second

metallic channels

32 and 34 are the grooves that are stamped to form on substrate 10, and the edge of groove is metallized with in order to ensure spreading into substrate 10 at the good electric continuity between

ground plane

12 and 22 with for the parasitism that prevents the signal between described

ground plane

12 and 22.

The size of resonant cavity 14 to 19 and groove 30 to 36 is according to the band pass filter that can obtain.The waveguide filter almost conventional together according to the response of filter of the present invention is identical.Yet the size of filter is distributed in the top and following length that reduced of substrate 10 owing to cavity.

The present invention can also have many optional patterns.A kind of filter that six cavitys are arranged has been described in the example.Also can be the filter that three cavitys are arranged, for example by eliminating

transverse groove

31,33 and 35.Yet when the quantity of cavity reduced, the advantage that its either side at substrate 10 all is provided with cavity will reduce, owing to small-sized some integrated problems that proposed of filter.

Similarly, have in filter greatly that cavity also is possible, under the condition that two faces of substrate are used, also can use the transverse groove that is positioned at mutual vertical plane.Waveguide filter just can fold self along two different directions then.

Shown cavity is the cavity of rectangle, but it also can be the filter with difform cavity, for example cylindrical or hemisphere face shape.That side that just corresponds to the cavity of ground plane need be the plane.

Cover 22 shown in the indication and pedestal 21 are made by metal.Also can use any material to make these building blocks so that its be conduction or covered by a conductive layer, thereby guarantee cavity conductivity performance.

As described above, shown is filter as an outdoor transmitter unit part.Filter is particularly suitable for such equipment.Yet such filter also can be applied in other microwave circuit.

Claims

1. A waveguide filter comprising at least three resonant cavities (14 to 19) coupled to each other, the filter is coupled to a microstrip circuit on a substrate (10), characterized in that at least one cavity (14 , 15, 18, 19) on one side of the substrate (10) and at least one other cavity (16, 17) on the other side of the substrate (10).

2. according to the described filter of claim 1, it is characterized in that: the face that is positioned at the cavity (14 to 19) with respect to substrate (10) is through the grounding plane (12,19) supported by substrate (10). 22) Electric closed.

3. The filter according to claim 2, characterized in that: the coupling between the at least two cavities on each side of the substrate is through grooves (32, 34) on the ground plane or by separating said cavities The planes (12, 22) of the cavity are formed.

4. The filter as claimed in claim 3, characterized in that the substrate (10) is cut with grooves (32, 34) and the edges of the grooves are metallized.

5. The filter according to claim 2, characterized in that: the coupling between the microstrip circuit and one of the cavity inlets of the filter is through a groove (30) on the ground plane (12) of the cavity , 36), the groove is located under the open microstrip line (11, 13).

6. according to the described filter of claim 1, it is characterized in that also comprising:

The first cavity (14) is located on the first surface of the substrate (10), the substrate is covered by the ground plane (12) penetrated by the first coupling groove (30), and the first microstrip line (11) is located on on the second face of the substrate (10) above the coupling groove (30), so that the filter is coupled to the microstrip circuit;

a second cavity (15) located on the first side of the substrate (10) and coupled to the first cavity (14) via a groove (31) in the first side;

The third cavity (16) is located on the second surface of the substrate (10), and is coupled to the second cavity (15) through the second coupling groove (32) passing through the substrate (10);

a fourth cavity (17) located on the second side of the substrate (10) and coupled to the third cavity (16) via a groove (33) in the second side;

a fifth cavity (18), located on the second surface of the substrate (10), and coupled to the fourth cavity (17) through a third coupling groove (34) passing through the substrate (10); and

The sixth cavity (19) is located on the first face and is coupled to the fifth cavity (18) through the groove (35) on the third side, and the substrate (10) is passed through by the fourth coupling groove (36). Covered by the ground plane (12), the second microstrip line (13) is located on the second surface of the substrate (10) above the fourth coupling groove (36), so that the filter is coupled to the micro belt on the circuit.

7. The filter according to claim 6, characterized in that, except for the coupling grooves (30, 32, 34, 36), the entire surface of the substrate (10) in contact with the cavities (14 to 19) Above, cover the substrate (10) with a ground plane.

8. An outdoor transmitting unit that transposes a signal from an intermediate frequency band to a transmitting frequency band, said unit includes making a circuit on a substrate (10) with microstrip technology, and said circuit includes an amplifying device (4, 6) . Transformation means (2, 3) and filtering means (5), characterized in that the filter means comprises a filter according to any one of claims 1-7.